The subject invention relates to the field of osteogenic proteins and pharmaceutical formulations thereof. More particularly, the subject invention involves pharmaceutical formulations designed to sequester osteogenic protein in-situ for a time sufficient to allow the protein to induce cartilage and/or bone formation.
Osteogenic proteins are those proteins capable of inducing, or assisting in the induction of, cartilage and/or bone formation. Many such osteogenic proteins have in recent years been isolated and characterized, and some have been produced by recombinant methods. For example, so-called bone morphogenic proteins (BMP) have been isolated from demineralized bone tissue (see e.g. Urist U.S. Pat. No. 4,455,256); a number of such BMP proteins have been produced by recombinant techniques (see e.g. Wang et al. U.S. Pat. No. 4,877,864 and Wang et al. U.S. Pat. No. 5,013,549); a family of transforming growth factors (TGF-.alpha. and TGF-.beta.) has been identified as potentially useful in the treatment of bone disease (see e.g. Derynck et al., U.S. Ser. No. 695,494 U.S. Pat. No. 5,125,978 which corresponds to EP 154,434); a protein designated Vgr-1 has been found to be expressed at high levels in osteogenic cells (see Lyons et al. (1989) Proc. Nat'l. Acad. Sci. USA 86, 4554-4558); and proteins designated OP-1, COP-5 and COP-7 have purportedly shown bone inductive activity (see Oppermann, et al. U.S. Pat. No. 5,001,691).
Various attempts have been made at developing formulations designed to deliver osteogenic proteins to a site where induction of bone formation is desired For example, certain polymeric matrices such as acrylic ester polymer (Urist, U.S. Pat. No. 4,526,909) and lactic acid polymer (Urist, U.S. Pat. No. 4,563,489) have been utilized, but these formulations do not sequester the osteogenic protein for a time sufficient to optimally induce bone formation. Collagen matrices have also been used as delivery vehicles for osteogenic proteins (see e.g. Jeffries, U.S. Pat. No. 4,394,370), but collagen frequently causes undesirable antigenic reactions in patients.